This invention relates to expansion joints and, more particularly, to composite expansion joints of the type employed in bridge deck constructions for accomodating movements between adjacent deck sections.
Composite expansion joints are conventionally used in those constructions, such as bridge structures and the like, wherein the relative movement between adjacent deck sections in response to temperature changes is too great to be accomodated by a single seal unit. These known composite expansion joints often consist of a series of laterally spaced elastic seals separated by rigid structural members or plates and extend lengthwise of the exapansion groove between the adjacent bridge deck sections.
In many of these prior composite joint assemblies, as disclosed in the U.S. Pat. Nos. 3,830,583 and 3,904,303 -- Becht et al assigned to the assignee of the present invention, it has been recognized that the rigid structural members tend to shift vertically and sometimes tilt about the longitudinal axes thereof as traffic moves thereacross, causing distortion of the expansion joint assembly and creating undesirable noise. Often, an excess of friction is generated upon relative sliding movement of the various components, causing wear thereof and creating additional noise. It is known in the prior art to employ various types of uplift restraint assemblies to limit the potential vertical lift and tilt of the rigid structural members. Such structures have included the provision of brackets on the structural members for engagement underneath a portion of the support bars which support the rigid structural members. Such brackets include pad portions bolted thereon for engagement against the undersurface of the support bar. However, due to bridge vibration and other types of related movement, the bolted connections between the aforesaid brackets and pads tend to become loose and in general cannot be easily adjusted to maintain a predetermined degree of contact between the pad and the support bar.